"There's been a collapse of what someone would call the 'athleisure market,' which is what some fashion magazine in New York would have done that 10 years ago, 10 years behind," Wilson said in a phone interview with Business Insider.

"We call it 'streetnic' — technical, stretch, street ... It's not fashion people trying to make this stuff look athletic. [The] Lululemon business is athletic wear that's made technical and just because [it] works so well technically, people wear it onto the street."

So what would make something "streetnic"? It would arguably the sort of apparel that puts technicality — like sweat-wicking, odor-killing attributes, all components to Lululemon's signature apparel — first, versus simply trying to appeal to a trend.

Wilson pointed to a few examples of brands with strong "technical" aspects. One was Rapha, a cycling-apparel brand.

Additionally, Under Armour started out as a brand known for apparel that kept you warm or cool, depending on the weather. Under Armour, however, has also recently announced that it would be launching a more fashion-centric line called Under Armour Sportswear.

"If Lululemon thinks it's in the athleisure business — that would be its biggest mistake," he said.